Samsung Galaxy Prevail II can be paired with Boost Mobile's no annual contract $55 Android Monthly Unlimited plan with Shrinking Payments. For every six on-time payments, the cost of Boost Mobile's Monthly Unlimited plan shrinks by $5, eventually getting down to as low as $40 a month for unlimited nationwide talk, text and picture messaging, Web, email and calls to 411. Payments do not need to be consecutive to qualify for the next savings milestone.